Temperature Effects on PN Junctions in Piezoelectric Semiconductor Fibers with Thermoelastic and Pyroelectric Couplings

摘要

We examine the effects of a uniform temperature change on PN junctions in piezoelectric semiconductor fibers. A one-dimensional model for thermally induced extensional deformation of the fibers derived previously from the macroscopic theory of thermopiezoelectric semiconductors is employed. With the linearized model, we present the analytical expressions of the built-in potential, carrier distribution, electric field, and polarization field in piezoelectric semiconductor PN junctions. A combined analytical and numerical analysis is performed on the built-in electromechanical fields in the junctions and their current-voltage relations. Numerical results show that homogeneous junctions have relatively good temperature stability, but heterogeneous junctions are sensitive to a temperature change that may be explored for thermally manipulating piezotronic devices. The difference between the temperature behaviors of the two types of junctions is determined to be due to the net amount of effective polarization charges at the junctions through pyroelectric and combined thermoelastic-piezoelectric couplings.